JPH0785488A - Optical pickup - Google Patents

Abstract

PURPOSE:To prevent a residual vibration due to an inertial force at the time of accessing at a high speed and to perform integration and reduction in size with a spatial allowance in which an optically integrated module can be assembled in a lens holder. CONSTITUTION:The optical pickup has the center of gravity coincident with the axial center and a vertical cylindrical shape, and a focus coil 5 and a track coil 6 are disposed at symmetrical positions of the inner periphery. The optical pickup is further provided with a lens holder 1 rotatably and axially slidably arranged between an inner yoke 7 and an outer yoke 8, and a sleeve 2 of a vertical cylindrical shape, supported at its inner periphery by an outer periphery of the holder 1, integrally arranged inside the yoke 8 and having magnets 9, 10 disposed between itself and the yoke 8. An axial center of the holder 1 is made to coincide with that of the sleeve 2 to be axially focus-controlled, and rotated to be track-controlled. A mirror 11 for forming an optical path is disposed between the lens 3 and an optically integrated module 4 in a lens holder hermetic space 1a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup device used in an optical recording / reproducing apparatus, and more particularly to a movable part of the optical pickup device.

[0002]

2. Description of the Related Art In a conventional optical pickup device, as shown in FIG. 6, a lens holder 21 is supported by a parallel leaf spring 22 and a cross leaf spring 23, and a focus coil 24,
The objective coil 27 is driven in the focus direction and the track direction by the track coil 25 and the magnet 26. In the optical system at this time, light is emitted from the laser diode inside the hologram laser unit 28, passes through the diffraction grating and the hologram, is vertically launched by the mirror, and is focused on the disk by the objective lens 27. Then, the light modulated / reflected on the signal surface of the disk returns to the hologram laser unit 28 along the reverse path.

The light that passes through the hologram again is diffracted by the hologram and focused on the photodetector. The photodetector that receives this light causes the hologram laser unit 28 to output focus and track error signals.

In the optical head disclosed in Japanese Patent Laid-Open No. 62-107442, the focus direction and the track direction are controlled by a control coil and a magnet which are completely separated from the optical system.

Further, for example, JP-A-63-23232
JP-A-63-168852, JP-A-2-3010
No. 25, No. Sho 63-135521, No. 2-51
In the respective publications of No. 15, a lens holder is supported by a support shaft or a guide shaft provided at the center, a focus coil and a track coil are arranged concentrically with the support shaft, and focus control is performed in the axial direction. Track control.

[0006]

In the configuration of the conventional optical pickup device shown in FIG. 6, since the base of the parallel leaf spring has a hinge structure, a large inertial force acts on the hinge when performing a high speed access operation. , It causes a shift deformation in the tracking direction and adds as noise to the tracking servo system,
The stability of the tracking servo system will be impaired. In addition, the light emitting part and the light receiving part of the laser light are housed in one module, and a compact optical integrated module is used.
The optical system is completed inside the lens holder to reduce the size of the optical pickup device. However, in the configuration shown in FIG. 6, there is no space for arranging the optical system, and it is difficult to downsize the entire device. .

The optical head disclosed in Japanese Patent Laid-Open No. 62-107442 does not use a hinge, but is completely separated from the optical system and is not suitable for miniaturization of integration.

The hinges of Japanese Patent Laid-Open Nos. 63-23232, 63-168852, 2-301025, 63-135521 and 63-5115 are also hinges. However, since the central support shaft guides sliding in the focus direction and the like, variations in focus control and the like will occur unless manufacturing accuracy is increased. Therefore, it is difficult to balance the lens holder, which hinders high-speed access. Further, since the support shaft is arranged at the center, there is no space for arranging the optical system, which makes it difficult to integrate and downsize the entire apparatus.

The present invention has been made in view of the above problems, prevents residual vibration due to inertial force at the time of high-speed access, and has a space for mounting the optical integrated module inside the lens holder, thus achieving compact integration. It is an object of the present invention to provide an optical pickup device that enables the above.

[0010]

In order to achieve the above object, the optical pickup device of the present invention is configured such that an objective lens is formed by a focus drive section and a track drive section in which a focus coil, a track coil and a magnet are concentrically arranged. In an optical pickup device in which focus control and track control of a lens holder provided on an upper surface are performed, a vertically-arranged cylindrical shape has a center of gravity aligned with an axis center, and a focus coil and a track coil are arranged at symmetrical positions on an inner peripheral surface. A lens holder that is rotatably and axially slidably disposed between the inner yoke and the outer yoke, and has a vertically-arranged cylindrical shape, and the outer peripheral surface of the lens holder is supported by the inner peripheral surface, The magnet is placed inside the yoke and the magnet is placed between it and the outer yoke. Is provided, and the axis of the lens holder is aligned with the axis of the sleeve, and at the same time, the lens holder is slid in the axial direction for focus control, and the lens holder is rotated for track control. It is configured to perform. . And, preferably, an optical integrated module is arranged on the upper surface of the lens holder at a position symmetrical to the objective lens, and a mirror for forming an optical path between the objective lens and the optical integrated module in a hollow portion inside the lens holder. Are arranged.

[0011]

In the optical pickup device of the present invention constructed as described above, current is passed through the focus coil and the track coil, and the focus control in the axial direction and the circumferential direction in the lens holder are performed by the magnetic field action with the magnet. When performing track control, the outer peripheral surface of the lens holder is supported by the inner peripheral surface of the sleeve, and the shaft centers of the both support the same and move smoothly. Further, in the optical pickup device of the present invention, the optical path between the optical integrated module and the objective lens is formed in the lens holder by the mirror, which enables downsizing and integration of the device.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an exploded perspective view of the optical pickup device of the present embodiment, which is concentric with a lens holder 1, a sleeve 2, a focus coil 5, a track coil 6, an inner yoke 7, an outer yoke 8 and a magnet 9,
Ten are arranged. 2 is an assembly perspective view of the optical pickup device, and FIG. 3 is a plan view of the device.
4 is a sectional view taken along line AA of FIG. 3, and FIG. 5 is taken along line AA of FIG.
It is a perspective view cut by a line.

The lens holder 1 is formed in a vertically-arranged cylindrical shape with a weight distribution such that the center of gravity thereof coincides with the axis, and is arranged between the inner yoke 8 and the outer yoke 9 so as to be rotatable and axially slidable. It is set up. Lens holder 1
The objective lens 3 and the optical integrated module 4 are arranged symmetrically in the diametrical direction of the upper surface, and the closed space 1a is provided in the lower portion of the objective lens 3 and the optical integrated module 4.
And two mirrors 11 are arranged to form an optical path between the lower surface of the integrated optical module 4 and the lower surface of the objective lens 3.

On the inner peripheral surface other than the closed space 1a, two focus coils 5 and two track coils 6 face each other to form a pair, and both are arranged in parallel. The optical integrated module 4 is a module in which a light emitting element and a light receiving element are integrated, and is called "Optical Data Storage".
(9-14 February 1992 San Jo
se, California) (SPIE-The I
international Society for
Optical Engineering, Volume
e1663, pp. 37-45), an example of the internal structure is described in detail.

The sleeve 2 has a vertically-arranged cylindrical shape and is integrally arranged inside the outer yoke 9, and focus and track magnets 9 and 10 are arranged between the sleeve 2 and the outer yoke 9. Also, the sleeve 2 is assembled so that the axis thereof coincides with the axis of the lens holder 1,
The inner peripheral surface of the sleeve 2 supports the outer peripheral surface of the lens holder 1 so that the lens holder 1 rotates smoothly.

As shown in FIG. 4, the lens holder 1
Is supported by the bottom surface of the outer yoke 9. Further, the drive system of the focus coil 5 and the like and the optical system of the optical integrated module 4 and the like are comprehensively controlled by the control unit of the optical recording / reproducing apparatus (not shown) using this optical pickup device.

Next, the focus and track control operation of this optical pickup device will be described. The laser light emitted from the optical integrated module 4 is guided to the objective lens 3 by the mirror 11 in the closed space 1a and is condensed on the optical disc. The laser light reflected and modulated by the disk signal surface travels in the current path in the reverse direction and returns to the optical integrated module 4 again. The control unit detects the returned laser beam and outputs a focus / track error signal. On the basis of this signal, an electric current is caused to flow through the focus coil 5 and the track coil 6, and the magnetic force acts on the lens holder 1 by the magnetic field action with the magnets 9 and 10, so that the lens holder 1 moves in the axial direction of the focus direction and the track direction. Moved in the circumferential direction.

In this way, unlike the conventional method of supporting by the supporting shaft located at the center of rotation, the method of supporting by the inner peripheral surface of the sleeve 2 allows the lens holder 1 to be manufactured without extremely increasing the manufacturing accuracy. The shaft center of 2 and the shaft center of the sleeve 2 are easily aligned with each other, so that the sleeve can rotate smoothly. As a result, residual vibration due to inertial force can be prevented, and high-speed access can be achieved.

[0019]

As described above, according to the optical pickup device of the present invention, the residual vibration is prevented from being generated due to the inertial force at the time of high-speed access, and there is a space for mounting the optical integrated module in the lens holder. Integration miniaturization can be achieved.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an optical pickup device of this embodiment.

FIG. 2 is an assembled perspective view of the above.

FIG. 3 is a plan view of the above.

4 is a cross-sectional view taken along the line AA of FIG.

5 is a perspective view of the device taken along the line AA of FIG.

FIG. 6 is a perspective view of a conventional optical pickup device.

[Explanation of symbols]

 1 Lens Holder 2 Sleeve 3 Objective Lens 4 Optical Integrated Module 5 Focus Coil 6 Track Coil 7,8 Inner Yoke, Outer Yoke 9,10 Magnet 11 Mirror

Claims (2)

[Claims] 1. An optical pickup device in which focus control and track control of a lens holder having an objective lens on an upper surface are performed by a focus drive unit and a track drive unit in which a focus coil, a track coil, and a magnet are concentrically arranged. In the vertical cylindrical shape, the center of gravity is aligned with the axis, the focus coil and the track coil are arranged at symmetrical positions on the inner peripheral surface, and the inner yoke and the outer yoke are rotatable and slidable in the axial direction. The lens holder is arranged vertically and has a cylindrical shape, and the outer peripheral surface of the lens holder is supported by the inner peripheral surface, is integrally arranged inside the outer yoke, and a magnet is provided between the outer holder and the outer yoke. A sleeve to be arranged, and the axis of the lens holder is aligned with the axis of the sleeve. At the same time, the lens holder is slid in the axial direction to perform focus control, and the lens holder is rotated to perform track control. 2. A mirror for arranging an optical integrated module on the upper surface of the lens holder at a position symmetrical to the objective lens, and forming an optical path between the objective lens and the optical integrated module in a hollow portion inside the lens holder. Claim 1 in which
The optical pickup device described.